U.S. Air Force Reserve Airmen assigned to the 913th Airlift Group, prepare to perform as many push-ups as they can in one minute during their physical fitness assessment test at Little Rock Air Force Base, Ark., April 1, 2017. The Air Force uses overall composite fitness score and minimum scores per component based on aerobic fitness (1.5-mile timed run), body composition (abdominal circumference measurements) and muscular fitness components (push-ups and sit-ups) to determine overall fitness. (U.S. Air Force photo by Master Sgt. Jeff Walston/Released)